| 摘要 |
PURPOSE: A voltage regulator is provided to constitute an overcurrent protection circuit of a fold-back type which is capable of operating even when a difference between input and output voltages is small. CONSTITUTION: A voltage regulator includes a reference voltage source outputting a reference voltage(100), a voltage dividing circuit dividing an output voltage, a feedback voltage electrode outputting a divided voltage, an error amplifier, a first transistor of a first conductive type, and an overcurrent protection circuit. The overcurrent protection circuit is composed of a second transistor of the first conductive type, a first resistor, a third transistor of a second conductive type, a second resistor, a fourth transistor of a first conductive type, and a differential pair. The third transistor is coupled between a node to which a control signal of the second transistor is applied and to a ground potential. The fourth transistor is coupled between an input power node and the second resistor. An output of an error amplifier is applied to a control node of the fourth transistor. The differential pair is coupled between the fourth transistor and the second resistor and includes a first and second input nodes.
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